DNA-binding protein VirE2 from Agrobacterium tumefaciens complexed with chaperone VirE1

Crystal structure of Agrobacterium tumefaciens VirE2 in complex with its chaperone VirE1: a novel fold and implications for DNA binding
 Here is the ribbon representation of the VirE1-VirE2 complex. The helix of VirE1 is colored blue. The N terminal domain of VirE2 is shown in red for α-helices and yellow for β-strands. The C terminal domain is shown in cyan for α-helices and magenta for β-strands. The inter-domain linker (residues 337-346) is shown as a black line. No electron density was observed for residues H342 and Q345 in the linker. Both domains form a TIM-barrel, consisting of α-helices and β-strands and resulting in a donut shape with β-strands in the interior and <scene name='VirE1/VirE2/Tim_barrel/8'>α-helices at the exterior. This barrel has a unique topology, instead of 8 repeats of the <scene name='VirE1/VirE2/Classical_tim_barrel/3'>αβ motif <font color='blue'>(blue) of a <scene name='VirE1/VirE2/Classical_tim_barrel/2'>classical TIM-barrel (e.g. 8tim), 4 <scene name='VirE1/VirE2/Bbaa_motif/1'>ββαα motifs (<font color='black'>yellow /<font color='red'>red ) are present in both the N- and C-terminal domains. The novel combination of the architecture and topology of this VirE2 domain allows its classification as a novel fold, termed the <scene name='VirE1/VirE2/Tim_barrel/10'>"VirE2 fold" (4 ββαα motifs are shown in <font color='red'>red, <font color='lime'>lime , <font color='black'>yellow , and <font color='blueviolet'>blueviolet , respectively).

Electrostatic interactions
<scene name='VirE1/VirE2/Interaction/8'>Electrostatic interactions between VirE1 <font color='blue'>(blue) and VirE2 are shown. Basic residues from both domains of VirE2 form electrostatic interactions (dashed lines) with acidic residues from VirE1. VirE2 <font color='lime'>N terminal domain is colored lime and the <font color='blueviolet'>C terminal domain - blueviolet.

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Additional Resources
For additional information, see: Nucleic Acids

Reference
Crystal structure of the Agrobacterium virulence complex VirE1-VirE2 reveals a flexible protein that can accommodate different partners., Dym O, Albeck S, Unger T, Jacobovitch J, Branzburg A, Michael Y, Frenkiel-Krispin D, Wolf G, Elbaum M., Proc Natl Acad Sci U S A. 2008 Aug 12. 105(32):11170-5 PMID:18678909